急性胁迫对团头鲂铁稳态及其相关基因表达的影响

Effects of acute stress on iron homeostasis and iron homeostasis related genes in Megalobrama amblycephala

为研究急性应激反应对鱼体铁含量及铁稳态相关基因的影响,以团头鲂为研究对象,通过腹腔注射皮质醇来模拟急性应激,在注射后不同时间点对团头鲂的血液、肠和肝脏进行取样,采用分光光度法测定血清和肝脏中的铁含量,采用实时荧光定量PCR对铁稳态相关基因的表达量进行检测。结果显示,皮质醇注射后血浆皮质醇显著升高,血浆中铁含量在4、8、10和12 h显著高于对照组,而肝脏中的铁含量在4、8、10和12 h时显著低于对照组。团头鲂肝脏中铁调素(hep)基因表达量显著增加,并分别在8和10 h达最大值,随后有所下降。肠道和肝脏中转铁蛋白基因(Tf)的表达量均呈先升高后下降的趋势。研究表明,急性应激下机体细胞内储存铁大量释放到体液中,造成病原感染和体内增殖风险增加;hep及Tf上调表达降低细胞内铁释放和促进体液铁向胞内蓄积,在鱼体内铁稳态的调控和固有免疫反应中发挥着重要的作用。

To study the effects of acute stress reaction on iron concentration and iron homeostasis in Megalobrama amblycephala, we stimulated stress response by intraperitoneal injection of cortisol. The iron content in serum and liver was determined by spectrophotometer, and the iron homeostasis related gene（hepcidin transferrin）expression were detected by quantitative real-time PCR at 0, 2, 4, 8, 10, 12, 24 and 48 h after cortisol injection.The results showed that the content of serum cortisol immediately increased significantly after injection, almost 10 folds compared with the control group, and gradually decreased backward. The content of serum iron in experimental group is higher than that in control group at 4, 8, 10 and 12 hours post injection（hpi）, but the content of liver iron led to the opposite results. Hepcidin m RNA expression in liver rose remarkably, reaching the maximum at 8 hpi and 10 hpi, respectively, and then descended to the normal level. The transferrin showed similar expression pattern, and reached the peak at 10 hpi. The result indicated that large release of intracellular iron into body fluid led to increased risk of pathogenic infection and proliferation in vivo. Hepcidin and Tf were involved in regulation of iron metabolism and inflammatory response under stress in M. amblycephala and may play important roles in iron homeostasis and innate immune system.